Air-cooled heat transfer device with integrated and mechanized air pre-cool system

ABSTRACT

A once-through dry adiabatic cooler having an integrated factory installed air pre-cooler system that is mechanized to move from a shipping position to an operational position.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to air-cooled heat transfer equipment.

Description of the Background

Air-cooled heat exchangers remove heat from a working fluid bytransferring that heat to the air. Air-cooled heat exchangers typicallyconsist of tubes connected to fins. The working fluid is sent throughthe inside of the tubes and the heat is conducted to the outside of thetubes and the fins. Air passing over the fins and tubes removes thisheat; one or more fans are generally used to move the air. The workingfluid can be a liquid, a gas, a condensing refrigerant, or any otherfluid that needs to have heat removed. The tubes are typicallyconstructed of copper, aluminum, or stainless steel but other metals andnon-metals have been used. Fins are typically made from copper oraluminum but other thermally conductive materials have been used.

For heat to be removed from the working fluid, the temperature of theworking fluid must be greater than the temperature of the air. Thegreater the temperature difference between the air and the working fluidthe less is needed to remove the heat; hence the less fan horsepower isneeded to move the air.

A known way to lower the ambient air temperature is by adiabaticcooling. With adiabatic cooling an amount of water is either sprayed inthe air or over some open-mesh panels. The water evaporates and coolsthe air with the air dry-bulb temperature approaching the wet-bulbtemperature. The adiabatically-cooled air will have a higher humiditylevel and a lower dry-bulb temperature than the untreated air. A lowerdry-bulb temperature will allow cooling at a lower airflow or coolingthe working fluid to a lower temperature both of which are desirableeffects.

There are various approaches for adiabatic cooling of air-cooledheat-exchangers. In one method the incoming ambient air passes throughpre-cooling system featuring an open-mesh panel that has been saturatedwith water. The panel can be saturated by a drip-feed, spray, or othermethod to saturate the panel. The water evaporates as the air passesthrough the panel cooling the incoming air. There are many variations onthe type and location of these panels but all have the incoming airpassing through a water saturated panel.

These pre-cooling systems are often supplied after-market and are alwaysshipped separately from the air cooled systems to which they are coupledand therefore require field installation.

SUMMARY OF THE INVENTION

The present invention features an air cooled heat transfer deviceincluding a factory installed air pre-cooling system coupled to andintegrated with the primary air-cooled heat transfer equipment, andfurther including a mechanism for shifting the air pre-cooling systemfrom a shipping position to an operational position.

The invention eliminates separation between the primary heat transferequipment and the air precooled system prior to shipment while keepingthe equipment within legal shipping dimensions which in turnsignificantly reduces equipment installation effort.

The factory assembled air cooled heat transfer device includingintegrated air pre-cooling system preferably includes the followingprimary components to facilitate proper operation and ensure non-permitshipping dimensions: pivoting water distribution header, removable waterdistribution and adiabatic pads, adjustable incremental framing,incremental adiabatic pad support angles, dual-function driptray/adiabatic pad bottom support, multi-functional drip pan, andadiabatic base frame support/unit structural enhancement.

The present integrated air pre-cooling system and air-cooled heattransfer device of the invention allows an air cooled system to operateat the same ambient dry bulb temperature in comparison to non-pre-cooledair equipment while achieving significantly higher heat rejectioncapability. Alternately, air cooled heat transfer equipment with an airpre-cooling system, can provide equivalent heat rejection whileoperating at a significantly higher ambient dry bulb temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of two V-type air cooled heat exchangers ofthe type that might be used in connection with the present invention.

FIG. 2 is a close up perspective view of the opposite ends of the twoV-type air cooled heat exchangers shown in FIG. 1.

FIG. 3 is a representation of the operation of a V-type air cooled heatexchanger of the type shown in FIGS. 1 and 2.

FIG. 4 shows a perspective view of two V-type air cooled heat exchangerson which adiabatic pads have been provided after market and site-mountedfor pre-cooling the incoming air.

FIG. 5 shows a close-up side cutaway view of one of the V-type aircooled heat exchangers shown in FIG. 3.

FIG. 6 is a representation of the operation of the V-type air cooledheat exchanger with adiabatic pre-cooling shown in FIGS. 4 and 5.

FIG. 7 is a perspective view of an integrated factory assembledintegrated air pre-cool system and air-cooled heat transfer deviceaccording to an embodiment of the invention with the air pre-cool systemin the retracted/shipping position.

FIG. 8 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in the retracted/shippingposition.

FIG. 9 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in a first partially deployedposition.

FIG. 10 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in a second partially deployedposition.

FIG. 11 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in a third partially deployedposition.

FIG. 12 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in a fourth partially deployedposition.

FIG. 13 shows a close-up perspective view of an embodiment of theinvention with the air pre-cool system in a fifth partially deployedposition.

FIG. 14 shows a tighter close-up perspective view of an embodiment ofthe invention with the top bracket of the air pre-cool system in theretracted position.

FIG. 15 shows a tighter close-up perspective view of an embodiment ofthe invention with the top bracket of the air pre-cool system in apartially deployed position.

FIG. 16 shows a tighter close-up perspective view of an embodiment ofthe invention with the top bracket of the air pre-cool system in asecond partially deployed position.

FIG. 17 shows a tighter close-up perspective view of an embodiment ofthe invention with the adiabatic pad and top bracket of the air pre-coolsystem in a fully deployed position and the top tube of the air pre-coolsystem in a partially deployed position.

FIG. 18 shows a tighter close-up perspective view of an embodiment ofthe invention with the adiabatic pad and top bracket of the air pre-coolsystem in a fully deployed position and the top tube of the air pre-coolsystem in a second partially deployed position.

FIG. 19 shows a tighter close-up perspective view of an embodiment ofthe invention with the adiabatic pad, top bracket and top tube of theair pre-cool system in fully deployed positions.

FIG. 20 is a perspective view of an integrated factory assembled airpre-cool system and air-cooled heat transfer device according to anembodiment of the invention with the air pre-cool system in the fullydeployed/operational position.

DETAILED DESCRIPTION

An example of a V-shaped cooler is shown in FIGS. 1 and 2. A framesupports two coil bundles each comprising a plurality of horizontallyarranged finned tubes in a V-shaped configuration. At one end of eachtube bundle, the tubes are connected at an inlet end to an inlet headerand to an outlet header. At an opposite end of each bundle, eachhorizontal tube is connected to an adjacent horizontal tube via a returnbend. A hot process fluid enters the inlet header via an inlet headerconnection and is then distributed to the tubes from the inlet header.Cooled fluid exits the tubes via an outlet header and returned to theprocess/system that headed the fluid. The frame supports a plurality offans at the top of the cooler and draws ambient air into the unit pastthe tubes and the fins and out the top of the unit.

The principles of operation of a V-shaped air-cooled heat exchanger ofthe type shown in FIGS. 1 and 2 is shown in FIG. 3. Hot process fluid,shown in red, enters the inlet header via the inlet header connection.From the inlet header, the hot process fluid travels transversely acrossthe heat exchanger, generally parallel to the horizontal. Heat from theprocess fluid dissipates through the coil tubes surface and out to thefins (not shown). Ambient air is drawn over the coil surface by the fanslocated at the top of the unit. Heat from the process fluid transfers tothe air and discharged to the atmosphere. Cool process fluid, shown inblue, exits the unit through the outlet headers.

An example of a V-shaped cooler with adiabatic pre-cooling pads is shownin FIGS. 4 and 5. A frame supports two coil bundles each comprising aplurality of horizontally arranged finned tubes in a V-shapedconfiguration. At one end of each tube bundle, the tubes are connectedat an inlet end to an inlet header and to an outlet header. At anopposite end of each bundle, each horizontal tube is connected to anadjacent horizontal tube via a return bend. A hot process fluid entersthe inlet header via an inlet header connection and is then distributedto the tubes from the inlet header. Cooled fluid exits the tubes via anoutlet header and returned to the process/system that headed the fluid.Adiabatic pads are mounted along and spanning both sides of the unitleft-to-right and top-to-bottom. A water distribution system drips wateronto the top of the pads to saturate them. Water that is not evaporatedfrom the pads is collected at the bottom of the unit and either send todrain or recirculated back to the top of the unit and returned to thepads. The frame supports a plurality of fans at the top of the coolerand draws ambient air into the unit through the saturated pads, past thetubes and the fins and out the top of the unit.

The principles of operation of a V-shaped air-cooled heat exchanger withadiabatic pads for pre-cooling the incoming air is shown in FIG. 6. Hotprocess fluid, shown in red, enters the inlet header via the inletheader connection. From the inlet header, the hot process fluid travelstransversely across the heat exchanger, generally parallel to thehorizontal. Heat from the process fluid dissipates through the coiltubes surface and out to the fins (not shown). The adiabatic systeminvolves fully wetting a fibrous pad located in front of the coil.Ambient air is drawn through the adiabatic pre-cooling pad by the fanslocated on top of the unit. The air is humidified as it passes throughthe adiabatic pad, decreasing the dry bulb temperature within a fewdegrees of the wet bulb temperature. This new air temperature isreferred to as the depressed dry bulb. This pre-cooled air is then drawnthrough the tube and fin surface, offering a substantial increase inheat rejection capability. Heat from the process fluid transfers to theair and discharged to the atmosphere. Cool process fluid, shown in blue,exits the unit through the outlet headers. In a recirculating watersystem, the water used to wet the adiabatic pads and which is notevaporated is collected at the bottom of the unit and recirculated to awater distribution system at the top of the pad. In a once-through watersystem, the water used to wet the adiabatic pads and which is notevaporated is collected and sent to a drain.

An example of an embodiment of the invention including a V-shapedair-cooled heat exchanger with integrated factory installed airpre-cooling system is shown in FIGS. 7 and 20. FIG. 7 shows the airpre-cooling system in the retracted position for shipping, and FIG. 20,shows the air pre-cooling system in the fully deployed operationalposition.

FIG. 8 shows a close-up perspective view of an embodiment of theinvention with the integrated air pre-cool system in theretracted/shipping position. Removable water distribution and adiabaticpads 3 are shown resting on dual-function drip tray/adiabatic pad bottomsupport 5, just above multi-functional drip pan 7. Pivoting waterdistribution header/tube 9 is pivotally attached to the frame of theV-shaped air-cooled heat exchanger. The integrated air pre-cool systemalso includes framing 11 attached to the frame of the V-shapedair-cooled heat exchanger, pivoting intermediate adiabatic supportelement 13 and translatable top adiabatic support element 15.

When the device is ready to be shipped, all the adiabatic pads are inthe position shown in FIG. 8, with respective top and bottom pads 3lying/stacked flat against one-another, with the top pad in frontof/external to the bottom pad. The water distribution tube 9 is in theretracted position, folded against the frame of the V-shaped air-cooledheat exchanger. The top adiabatic support element 15 is in theretracted/down position, and the intermediate support element 13 is inthe down/retracted position. According to an alternative embodiment, thetop adiabatic support element 15 may be in the deployed/top position(see, e.g., FIG. 16). The device is shipped in this position.

When the device has arrived at its installation site, thedeployment/positioning control system 17 is activated by anoperator/installation technician causing the elements of the pre-coolingsystem are automatically moved sequentially into a fully deployedoperational configuration. FIG. 9 shows the first step of this processin which the top adiabatic pad is raised towards the operation positionby a adiabatic pad positioning mechanism 19. At this stage, the waterdistribution tube 9 and intermediate support element 13 remain in theretracted position. The top adiabatic support element 15 remains in theshipping position, whether in the lowered position or in the finalposition.

FIG. 10 shows the top adiabatic pad beginning to move into finalposition, with the remaining elements of the pre-cool system in theirshipping state. While the figures show only one set of top pads movinginto deployment configuration, in actual operation, all top pads aremoved simultaneously into deployed/operational configuration. FIG. 11shows the top adiabatic pad moved into its final and operationallocation/configuration.

When the top pads have moved into their final location, the intermediatepad support elements are automatically raised towards their finaloperational configuration by pad support element positioning mechanisms21, see FIG. 12 (intermediate pad support element moving towards finaloperational configuration) and FIG. 13 (intermediate pad support elementarrived at final operational configuration).

In a next step, if the top adiabatic support element is not already inthe fully deployed and raised position, it will be automatically movedinto that position. FIG. 14 shows the top adiabatic pad support elementin the lower (preferred shipping) configuration. FIG. 15 shows the topadiabatic pad support element moving towards its fully raised andoperational configuration, and FIG. 16 shows the top adiabatic padsupport element having been moved into its fully raised and operationalposition (and optional, less preferred shipping position).

Once the top adiabatic pads are in operational position, and the top andintermediate adiabatic support elements are likewise in theiroperational positions, the water distribution tube is automaticallyrotated out of its shipping position into its operational position bywater distribution tube positioning mechanism 23, see, e.g., FIGS. 17and 18.

The adiabatic pad positioning mechanism, adiabatic pad support elementpositioning mechanisms, and the water distribution tube positioningmechanism are connected to and activated by positioning control system17.

FIG. 19 the top adiabatic pad, the top adiabatic pad support elementbracket and the water distribution tube of the air pre-cool system infully deployed positions, with the water distribution tube nested in anotch in the top of the adiabatic pad.

FIG. 20 is a perspective view of an integrated factory assembled airpre-cool system and air-cooled heat transfer device according to anembodiment of the invention with the air pre-cool system in the fullydeployed/operational position. Once the integrated air pre-cool systemis fully deployed into the operational configuration, it operates asdescribed with respect to FIGS. 4-6.

Various mechanical and control systems for moving the elements of theair pre-cool system from the shipping positions into their operationalpositions are well within the ability of the person of ordinary skill tomake and use and the invention is not intended to be limited to anyspecific mechanism or control system for doing so.

1. A dry adiabatic cooler, comprising: a frame; two tube bundlesarranged in said frame in a vertically oriented V-shape; each of saidtwo tube bundles having an inlet header and an outlet header, each saidinlet header configured and located to receive hot process fluid and todistribute said hot process fluid to a corresponding tube bundle andeach said outlet header configured and located to receive cooled processfluid from said corresponding tube bundle; at least one fan located andconfigured to move air through said two tube bundles; a plurality ofupper adiabatic pads and a plurality of lower adiabatic pads mounted insaid frame adjacent to an air intake side of each said two tube bundles,said plurality of upper adiabatic pads having upper adiabatic padshipping positions laterally adjacent respective ones of said pluralityof lower adiabatic pads and upper adiabatic pad operational positionsabove respective ones of said plurality of lower adiabatic pads; a waterdistribution system comprising one or more water distribution tubesconfigured and located to wet and cool said air prior to being movedthrough said two tube bundles; and a water collection tray located belowsaid adiabatic pads and configured to collect water draining from saidadiabatic pads.
 2. A dry adiabatic cooler according to claim 1, furthercomprising a control system configured to cause said plurality of upperadiabatic pads to move from respective shipping positions to respectiveoperational positions.